The present invention is directed generally to an apparatus and method for sorting articles. More particularly, the present invention is directed to an apparatus and method for sorting an article according to combined plural criteria, including the article's volume, length, diameter, weight, shape, density, color and/or surface quality. A novel means for obtaining dimensional data about the article, including the article's volume, diameter and overall length, is disclosed.
Apparatus for sorting articles according to weight only and according to a combination of color and weight is known. See U.S. Pat. No. 4,106,628 issued Aug. 15, 1978 for "Sorter For Fruit And The Like", incorporated herein by reference. Apparatus for sorting articles according to surface quality, physical size and/or color is also known. See U.S. application Ser. No. 430,068 filed Sept. 30, 1982, now U.S. Pat. No. 4,515,275, entitled "Apparatus And Method For Processing Fruit and The Like." See also U.S. Pat. No. 4,246,098 issued Jan. 20, 1981 entitled "Method And Apparatus For Detecting Blemishes On The Surface Of An Article." The sorting apparatus disclosed in the '098 patent examines an article while it is in free fall through an examining region and the optics and processing circuitry associated with that system are complex and expensive to manufacture.
The present invention has particular application in sorting commodities such as fruit which must be sized by volume or diameter. The most common prior art apparatus for sorting fruit according to volume comprises a series of sequential rollers which are spaced apart by a distance which increases from one pair of rollers to the next. The rollers are rotated causing the fruit to be transported from one end to the other. The fruit falls through the roller conveyor if the distance between the pair of rollers over which the fruit is being transported exceeds the diameter of the fruit. This apparatus, known as a "dimensional sizer", is mechanically complex and cannot be integrated with electronic sorting apparatus for sorting on the basis of plural criteria.
It is desirable to sort articles according to any combination of volume, diameter, weight, shape, density, color and/or surface quality. Prior art sizers do not provide this versatility. The present invention is directed to a simple, inexpensive but versatile apparatus for optically sizing articles such as fruit and for sorting those articles according to any combination of volume, length, diameter, weight, shape, density, color and/or surface quality.